The present invention relates to an athletic shoe having a novel feature directed to enhancing its safety and practical utility. More specifically, the athletic shoe of the present invention incorporates a releasably locking, plug-in module that is removably insertable into a recessed retaining receptacle in the sole of the shoe. The plug-in module may include a battery and an externally visible light emitting device interconnected via circuitry that includes a switch for energizing the light emitting device in response to pressure exerted upon it by the foot of the wearer during walking or running.
There are a number of references in the patent literature that depict various methods for incorporating light emitting elements and batteries to energize them into various portions of a shod in order, e.g., to provide a visually distinctive shoe. In a majority of the examples found in the prior art, the light emitting device, as well as the batteries, have been incorporated into the heel portion of the sole of a dress shoe. The advantage of this configuration is that the heel of a dress shoe generally provides sufficient volume to easily accommodate the electronic apparatus, and is constructed of a rugged, non-resilient material that protects the light and battery and, in a translucent version, can also serve as a light conductor or spreader.
For example, U.S. Pat. No. 4,253,253, British Patent No. 444,392, and Belgian Patent No. 570614, all illustrate womens high heel dress shoes incorporating a battery in the hollow interior of the heel of the shoe. Alternatively, U.S. Pat. Nos. 1,597,823, 2,931,893, 4,014,115, and 5,052,131, as well as European Patent publication No. EP-121-026-A, depict lighted dress and casual shoes incorporating a raised or block-type of heel having a recessed inner portion for receiving the battery.
There may be several reasons for incorporating an active light emitting device into a shoe, e.g., to enhance the night safety of the wearer, to provide special visual effects at entertainment events, or to assist in certain biomechanical testing and measurements.
Thus, while it is known to incorporate passive reflectors, including reflective tapes and the like, on the equipment or apparel of athletes, such as joggers or bicyclers to increase their visibility, and hence, safety, at night, it is necessary for the purely reflective elements to be illuminated by an external, active light source, such as the beam of an automobile headlight, in order for them to function. Footwear that incorporates its own built-in, active light source, and which, therefore, does not depend on an external source for illumination, can provide a higher level of visibility and safety than those that are purely reflective in nature.
Further, the incorporation of active light sources into the shoes of participants engaged in certain entertainment events, such as those worn by dancers, marching bands, athletes and the like, can achieve special, entertaining visual effects in low light conditions, particularly where it is desired to call attention to the participants' feet. For example, a marching band equipped with such footwear can present an impressive spectacle, as the individually-illuminated feet of its members move in synchronous unison.
The provision of an active light source on the shoes worn by test subjects engaged in certain walking and running motion studies can also enhance the ability of scientists and biomechanical engineers to measure and analyze those activities from a human engineering or sports medicine standpoint. Such studies frequently involve photographing a particular point or reflective target disposed on the foot or ankle of a test subject with high-speed motion picture equipment, then digitizing the motion of that point for subsequent analysis with a digital computer. The incorporation of an active point light source on the shoe at the point under examination can enhance the testing procedure because the active light source is photographically more distinct, and hence, easier to photograph. Additionally, the light source can be adapted with a pressure- or acceleration-sensitive switch to illuminate selectively when a certain preset force or acceleration is exerted upon it during a particular activity. Thereby, the forces or accelerations acting on the shoe during various athletic endeavors can be better analyzed.
A review of the references in the prior art reveals that the incorporation of a light-emitting device into the sole of an athletic shoe is complicated by the specific qualities of resiliency, flexibility, and support required of such a shoe's sole during athletic activities. An improperly designed athletic shoe sole that does not provide the desired degree of support, protection, and comfort for the athlete is unacceptable. Thus, it is not a simple matter of taking the teachings of the prior art, directed to various types of dress and casual shoes having block or high heels and essentially rigid soles, and incorporating the designs for their lighting device and power sources in generally the same configuration into an athletic shoe.
A further limitation of the designs of the prior art, to the extent that they can be incorporated into athletic shoes, relates to their relative inaccessibility within the shoe, with a concomittant lack of replaceability and maintainability of their various components, including their batteries, light sources, and switching components.